1. Field of the Invention
The present invention relates generally to the field of electrical conduction mechanisms for delivering electricity to homes and businesses. More specifically the present invention relates to a cord plug engagement apparatus such as a wall outlet for receiving and engaging prongs of appliance cord plugs and delivering electric current into at least one of the prongs, the apparatus having locking means which lock the prongs into the apparatus to prevent plug removal and insertion of objects by children. The essential elements of the apparatus are a face plate having prong passing ports and a face plate front surface and a face plate rear surface, a slide bolt structure constrained by mounting means on the face plate rear surface to slide parallel to the face plate, with locking bolts which slide to enter prong openings at the prong free ends and thus to lock the prongs within the apparatus, and a slide bolt structure displacement mechanism for manual movement by a user which in turn moves the slide bolt structure so that the bolts enter or retract from the prong openings. A bolt stop structure is optionally provided which obstructs the movement of the bolts across the prong entry paths prior to insertion of prongs into the apparatus, so that the prongs do not strike and damage the bolts during insertion.
2. Description of the Prior Art
There have long been plug prong engaging receptors such as outlets for releasibly holding the prongs of a cord plug within the outlet. These prior outlets and related structures have been in general inefficient and costly.
One such prior receptor is that of Ursich, U.S. Pat. No. 5,129,836, issued on Jul. 14, 1992. Ursich includes locking elements that are uniquely arranged to engage the typical punch holes provided in the male prongs of an electrical plug. Without other tools, the locking elements of the invention are locked in position by depression of an exterior arranged actuator which is also used to permit the plug to be easily removed.
Burke, Jr., U.S. Pat. No. 5,073,122, issued on Dec. 17, 1991, discloses a lock-out enclosure for power connectors. Burke, Jr. includes a tubular enclosure that is only slightly larger than the connector. A cap is installed on one end of the tubular enclosure. Installation of the cap onto the power line is made possible by a radial slot extending part way therethrough. After the cap is located on the power line, the tubular enclosure is slid over the connector and onto the cap. The cap is then permanently attached to the tubular enclosure using the adhesive or locking means to form an enclosure locking assembly. The enclosure assembly is slid over the associated connector to prevent access to the connector.
Boyer, U.S. Pat. No. 5,055,057, issued on Oct. 8, 1991, reveals an electric plug lock. Boyer includes a device which has bolt portions which removably slide into the openings provided at the distal end of virtually all cord plug prongs to lock the plug prongs into the device. Ursich, U.S. Pat. No. 5,281,162, issued on Jan. 25, 1994, discloses another variation of the prong opening engaging bolts in a receptor, which in this instance are metal balls which ride into the prong openings upon lock engagement.
Other generally related art includes Sleverman, U.S. Pat. No. 4,812,131, issued on Mar. 14, 1989 for an electrical plug apparatus; Belsky, U.S. Pat. No. 4,957,446, issued on Sep. 18, 1990, for a lockout device for electrically operated equipment; Herbert, U.S. Pat. No. 5,176,527, issued on Jan. 5, 1993, for an apparatus for preventing the use of an electrical device; Brend, U.S. Pat. No. 5,330,361, issued on Jul. 19, 1994, for an electrical plug locking device; Perkins, et al., U.S. Pat. No. 5,409,393, issued on Apr. 25, 1995, for a locking mechanism for a ribbon cord; Aikens, U.S. Pat. No. 5,666,829, issued on Sep. 16, 1997, for a plug lock; Garrison, U.S. Pat. No. 5,480,318, issued on Jan. 2, 1996 for a childproof electrical plug; and Reed, U.S. Pat. No. 5,941,724, issued on Aug. 24, 1999, for a lockable female electrical receptacle.
It is thus an object of the present invention to provide a safety locking system which may take the form of plug prong engaging outlet, to prevent removal of the plug from the outlet by children and the consequent danger of insertion of some other object into the outlet.
It is another object of the present invention to provide such a locking system and apparatus which accepts conventional, standard plugs, so that no modification need by made to the vast numbers of existing appliance cords in use today.
It is still another object of the present invention to provide a locking system and apparatus which includes means for retracting electrical contacts out of the plug prong entry paths of plug prongs when the apparatus is not in use so that a foreign object fitted into any of the apparatus plug prong entry paths, such as by a child, does not make electrical contact and therefore does not cause injury.
It is finally an object of the present invention to provide such a system and apparatus which is relatively inexpensive to manufacture and which is sturdy, durable and easy to use.